The worm, which runs after the Windows XP boot-up music has played, deletes DLL and INI files to cause Windows to fail. It spreads automatically via an email entitled "Listen and Smile" and alters home page settings on Internet Explorer.

"It might be confusing to users because it says 'I am seeing you'," says Mikko Hypponen, director of antivirus research for F-Secure. "It's the only [worm] I have found speech on, but it is not too advanced because it is written is Visual Basic."